S19·E3 Transcendence

After fending off the Hoppers who disappeared into another dimensional rift, Yusuke reveals he was told of Decade by a mysterious man. When Ai and her task force go to investigate Mount Hitoki, a black mist begins to rise from within, signaling the revival of N-Gamio-Zeda. Resurrected by the dimensional chaos, he uses his miasma to convert humans into Grongi. While Yusuke saves Ai and takes her to the hospital, Tsukasa fights the Grongi alone. A dying Ai requests Yusuke to overcome his angst and fight to protect everyone's smiles, and so Kuuga and Decade work together to destroy the remaining Grongi. N-Gamio-Zeda, in a last effort, absorbs all the Grongi to power himself up, but he is ultimately overpowered by both Decade and Kuuga, who destroy him with a combo attack.